This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Paralysis following stroke stems not only from the loss of neurons killed by the stroke but also from the loss of neurons lying dormant in the stroke hemisphere. One of the reasons viable neurons become dormant (down-regulated) is because of excessive interhemispheric inhibition imposed on them through transcallosal pathways from the nonstroke hemisphere. Our challenge in neurorehabilitation is to restore excitability and voluntary control of these down-regulated neurons in the stroke hemisphere. Supression of the source of this excessive interhemispheric inhibition can be achieved with the noninvasive method called repetitive transcranial magnetic stimulation (rTMS). It is known that low-frequency rTMS has disruptive or depressant effects on the underlying neurons. Furthermore, recent work has shown that the depressant effect of low-frequenycy rTMS can be magnified and prolonged by preceding it with a period of high-frequency (6-Hz) priming rTMS. And so, it is logical to apply 6-Hz primed low-frequency rTMS to the non-stroke primary motor area (M1) to depress excitability in that hemisphere, thereby increasing excitability of M1 in the stroke hemisphere. But there is risk of inducing a seizure in people with stroke with this treatment, which may outweigh the potential goodness of the treatment. Thus, the aims of the proposed study are to determine the efficacy, mechanism, and safety of 5 treatments of 6-Hz primed low-frequency rTMS applied to the non-stroke hemisphere to promote recovery of the paretic hand. Furthermore, we will explore whether efficacy can be enhanced by combining the rTMS with motor learning training.